Oil burner

ABSTRACT

A gun type oil burner having a metering plate with adjustable orifices arranged between the burner tip and the burner fan in which the adjustable orifices are peripherally disposed along the inner surface of the blast tube and are axially lined with radial and spirally arranged channels on the inside of the frusto conical tip of the burner.

United States Patent Flournoy et al.

[ OIL BURNER [72] Inventors: Norman E. Flournoy; Julian l-l. Dancy, bothof Richmond; Raymond Trippet, Highland Springs, all of Va.

[73] Assignee: Texaco Inc.

[22] Filed: Oct. 5, 1970 [21] Appl. No.: 78,069

521 u.s.c1 ..431/265,43l/l82 [51] Int. Cl ..F23q 3/00 58 Field of Search..431/1s1, 182, 183, 185,265;

[56] References Cited UNITED STATES PATENTS De Lanceym, 431/265 X [451Sept. 26, 1972 3,143,159 8/1964 Smithson ..43l/265XPrimaryExaminer-Edward G. Favors Attorney-Thomas H. Whaley, Carl G. Reisand L. H. Phelps, Jr.

[5 7] ABSTRACT A gun type oil burner having a metering plate withadjustable orifices arranged between the burner tip and the burner fanin which the adjustable orifices are peripherally disposed along theinner surface of the blast tube and are axially lined with radial andspirally arranged channels on the inside of the frusto conical tip ofthe burner.

4 Claims, 7 Drawing Figures PATENTED 1972 3,694,136

. SHEET 1 [1F 3 PATENTED E I972 3.694.136

sum 2 OF 3 FIG. 2

on. BURNER The present invention relates to an oil burner and morespecifically to a burner of the so-called gun type wherein a spraynozzle for liquid fuel projects a conical pattern of finely atomizedfuel particles into a highly turbulent flow of air emanating from ablast tube.

More specifically, the invention concerns a structural arrangement forimproving and facilitating the efficiency of combustion. Hithertoinnumerable expedients have been proposed for effecting combustion. Ingeneral, these have sought to produce the ideal intermixture of finelydivided liquid fuel particles in a stream of air. This demands not onlyan extreme fineness of subdivision of the oil particles but a highdegree of turbulence or intermixing, such that the particles areuniformly and fully distributed throughout the oxygen stream.

The present invention achieves this effect in large measure by providinga blast tube in which the air draft flowing axially therethrough issubdivided into annularly spaced, separate metered columns of air justinside the inner surface of the blast tube. Preferably the columns areformed by passing the air through orifices or jets from a higher into alower pressure zone in order to form directed air jets. These segregatedand metered streams of air are, in effect, jets, and they are directedinto separate channels formed on the inner face of the frusto-conicalchoke at the end of the blast tube.

To do this, the extremity of the blast tube is provided with an end conetapering in a downstream direction, and having a restricted centralopening coaxial with the blast tube. The inner surface, however, isformed with a series of spirally arranged channels so that the airimpacting the channels is rotated spirally about the axis of the blasttube as it moves outwardly through the orifice in the end cone. Also,each channel independently receives one of the air columns. The netresult is high turbulence in the area of the liquid fuel spray and,accordingly, improved and more efficient combustion.

Referring now to the figures of the drawing wherein the one illustratedembodiment of the invention is disclosed in detail,

FIG. 1 is an oblique view of the blast tube of a gun type burnerembodying the present invention, portions being broken away to show theinternal structure,

FIG. 2 is a diametrical section taken on the axis of the burner of FIG.1,

FIG. 3 is a transverse section thereof taken on the line 3-3 ofFIG. 2,

FIG. 4 is a section taken on the line 4--4 of FIG. 2,

FIG. 5 is similar to FIG. 4 of a modified construction, and

FIGS. 6 and 7 are elevations of two plates which make up the adjustableorifice arrangement of FIG. 5.

The embodiment shown comprises a blast tube 10 excluding theconventional remainder of the gun type burner assembly, such as,-forexample, the blower motor, ignition control, pumps, etc., which arefamiliar to those skilled in the art. Nevertheless, it is to beunderstood that the blast tube projects from a burner of typicalconstruction which is supplied from its right hand extremity with apressurized flow of air from a suitable high pressure fan or blower notshown. Similarly, liquid fuel is supplied thru a central coaxial conduitI2 supported by frame 14, as indicated, and

bearing at its left hand extremity a nozzle. 16. The frame also carriesinsulators l8 and electrodes 20 for initiating combustion. The entireinternal structure of nozzle and ignition electrodes is, in turn,located and supported in the blast tube by an air plate assembly.

The air plate assembly, which forms an important part of the presentinvention, comprises an inner air plate 22 which is shown in somewhatgreater detail in FIGS. 2 and 4 to which is attached an outer controlplate 24 which is held flatwise thereon by machine screws 26 shown inFIG. 4. Both of the plates are circular, with a peripheral diameterapproximately equal to that of the interior diameter of the tube 10 sothat they may fit snugly therein and can be slid into position axiallyfrom the rear end of the gun barrel in the usual way.

The details of the air plate assembly, as shown more clearly in FIGS.2-4 are characterized by peripheral, annularly spaced recesses 28 cutinto the periphery of air plate 22. In the specific embodimentdisclosed, the recesses 28 comprise U" shaped grooves which faceradially outward of the circular disc 22 and are equally spaced alongits periphery. Therefore, annularly spaced columns of air under pressureare released through these recesses along the inner surface of theburner tube 10 in an axial direction. So thatthe quantity of air passingthrough, as well as, the form of the columns or jets of air can bevaried, the control plate 24 is also provided with peripheral recessesor apertures'of identical shape and configuration. As a result, byrotating the cover plate or disc 24 with respect to the disc 22, theform and area of the vertical apertures may be selectively varied inaccordance with a predetermined pattern. Rotational adjustment of thetwo plates is enabled by fasteners 26 previously mentioned whichthreadedly engage the plate 22 and pass thru suitable slots 30 in thecover plate 24.

The plate assembly, as previously intimated, is also apertured toreceive the ignition insulators l8 and the fuel tube 12 of the burnernozzle 16. For example, suitable elongated apertures 32 about theinsulators l8 permit relative adjustment of the two plates. Thus theoperator, by known ways, simply by loosening fasteners 26 can rotate thetwo plates 22 and 24 with respect to one another to select theappropriate air through the end cone. This, in substance, provides aseries of annularly spaced, adjustable jet orifices which, combined witha substantial air pressure on the upstream side of the orifice plate,discharges spaced columnar jets of air. Also, a few additional annularlyspaced apertures 34 are provided to supply a necessary fraction of airthrough to the central part of the tube and about the nozzle 16 forblowing the ignition spark and cooling the nozzle.

Referring now to the end cone or air nozzle, this comprises afrusto-conical member 36 which engages the downstream extremity or tipof the blast tube of the burner as at 38 and is provided with a centralaperture of substantially lesser diameter than that of the burner tube.

FIGS. S-7 show an alternate design of the air plate which is effectiveat low flow rates. The air passages 42 and 44 are smaller and theiradjustment is less critical.

As previously mentioned, the choke or end cone is frusto-conical inshape and tapered inwardly in a downstream direction to facilitate theoutward flow of a compact jet stream of turbulent air.

The inner surface of the end cone is provided, as previously stated,with a series of radial, and at the same time, spirally directedchannels on its inner surface. This is effected by plates or dividers 40which project from the. inner surface of the end cone in an inwardlyextending axial direction, at the same time extending from a point atthe inner surface of said tube barrel, radially inwardly therefrom, butat an acute angle to the radius of the barrel. V

Stated in another way, the several plates 40 each are arranged to directthe air impinging therebetween in a conical plane toward the axis of thebarrel and the extremity of the air cone but at a slight angle to thetrue radius of the cone. Since each of the channels thus formed makes asimilar angle with its radius, the various streams of air released bythe channels, therefore, are all spiralled in essentially the samerotational direction. Moreover,- since the mass of air flow is directeda substantial distance radially inwardly, its rate of flow iscorrespondingly increased so that it leaves the frusto-conical end ofthe burner tip as a whirling jet in a high state of turbulence.

An important feature of the present invention, as indicated more or lessdiagrammatically in FIG. 1, is the location of the air plate assembly sothatthe separate and individual, annularly spaced columns of air eachimpinge directly and separately into the central portion of one ofthe-channels on the inner face of the end cone.

While applicant does not wish to be bound by a statement of theory it isfelt that the provision of separate jets of air projected into-thespirally arranged channels of the burner tip provides a novel andeffective way of maintaining .a high efficiency transition of the airflow into a highly turbulated, spirally flowing draft of air downstreamof the end cone. Thetotal air flow is thus given a more turbulent motionby this method than by methods of other oil burners.

In point of fact, tests have shown that this design affords excellentflame shape and uniform temperature distribution throughout thecombustion chamber. The following table gives a comparison between theconventional commercial burner (A) using an end cone and an internal airdeflector, and a burner modified in accordance with the presentinvention by substituting the air plate assembly and end cone as calledfor herein (B). Also, in order to permit operation with the restrictionintroduced by the air plate, burner (B) was further modified by drivingthe air fan at 3,450 RPM as against a 1,725 RPM rotational speed of thefan in burner (A).

EXCESS AlR PERCENTAGE SMOKE NO. A 18 3.6 B l9 0 Also, inaccordancewith-the present invention, by maintaining a substantial pressure, as,for example, 2.0 inches of H 0, upstream of the air plate, the burnerinherently overcomes heavy pulsations which are common in manyinstallations of the conventional commercial burners. It is believed,although applicant does not wish to be bound by this statement oftheory, that the high pressures form a base area, highly resistant topulsation.

Stated, therefore, in another way, the combination of adjustable jetorifice plate, with the substantial upstream air pressure necessary todrive columnar jets of air thru the plate has a multiple function ofboth resisting burner pulsation, and, in combination with registeringspiral channels in the burner tip, effecting improved combustion.

We claim: 1

Lin a gun type oil burner having' 'a gun barrel or 'blast tube suppliedwith a blast of air under substantial pressure, a fuel nozzle coaxiallyarranged in the vicinity of the downstream extremity of said gun barreland supplied with liquid fuel to form a predetermined pattern of highlyatomized fuel particles and means for igv niting said fuel, theimprovement which comprises a circular air plate assembly transverselyoccupying the interior of said blast tube upstream of said nozzle, andprovided with a plurality of annularly spaced orifices arranged adjacentto the periphery thereof, said peripheral orifices being adjustable formetering and controlling air flow therethrough,

said air pressure in said blast tube being sufficient to provide aseries of annularly spaced, independent, axially flowing jet columns ofpressured air through said orifices and along the inner wall of saidblast tube,

the end of said gun barrel comprising a frusto-conical member inclinedin a downstream direction and having a coaxial, restricted centralaperture on the inner surface of said frusto-conical member, and havingseparate, annularly spaced channels extending from the inner wall ofsaid gun barrel to said central aperture and in a frusto-conicaldirection and at an acute angle to the radius thereof in correspondingdirections to cause said air to flow in a spiral direction through theextremity of said burner tip,

' said radial channels in the end cone and said air plate assembly beingso arranged that the said independent columns of air formed by said airplate assembly, impinge the central portion of each of said channels.

2. A gun type burner as called for in claim 1 wherein said circular airplate assembly comprises a plurality of coaxially arranged plateshavingannular, peripherally spaced orifices adapted to register in oneangular position thereof, and

means for rotationally adjusting said plates relative to one another,such as to enable predetermined restriction of the effective opening ofsaid orifices.

3. A gun type oil burner as defined in claim 1 wherein the annularlyspaced orifices adjacent to the periphery. of said circular air plateassembly comprise radially inwardly extending recesses from theperipheral margin thereof, such that the inner wall of the blast tubeforms a portion of the margin of each said orifice.

4. A gun type oil burner as defined in claim 1 wherein said circular airplate assembly is provided with adjustable orifice means in the centralportion thereof, adapted to provide a limited flow of air to the centralpart of the blast tube about the fuel nozzle.

1. In a gun type oil burner having a gun barrel or blast tube supplied with a blast of air under substantial pressure, a fuel nozzle coaxially arranged in the vicinity of the downstream extremity of said gun barrel and supplied with liquid fuel to form a predetermined pattern of highly atomized fuel particles and means for igniting said fuel, the improvement which comprises a circular air plate assembly transversely occupying the interior of said blast tube upstream of said nozzle, and provided with a plurality of annularly spaced orifices arranged adjacent to the periphery thereof, said peripheral orifices being adjustable for metering and controlling air flow therethrough, said air pressure in Said blast tube being sufficient to provide a series of annularly spaced, independent, axially flowing jet columns of pressured air through said orifices and along the inner wall of said blast tube, the end of said gun barrel comprising a frusto-conical member inclined in a downstream direction and having a coaxial, restricted central aperture on the inner surface of said frusto-conical member, and having separate, annularly spaced channels extending from the inner wall of said gun barrel to said central aperture and in a frusto-conical direction and at an acute angle to the radius thereof in corresponding directions to cause said air to flow in a spiral direction through the extremity of said burner tip, said radial channels in the end cone and said air plate assembly being so arranged that the said independent columns of air formed by said air plate assembly, impinge the central portion of each of said channels.
 2. A gun type burner as called for in claim 1 wherein said circular air plate assembly comprises a plurality of coaxially arranged plates having annular, peripherally spaced orifices adapted to register in one angular position thereof, and means for rotationally adjusting said plates relative to one another, such as to enable predetermined restriction of the effective opening of said orifices.
 3. A gun type oil burner as defined in claim 1 wherein the annularly spaced orifices adjacent to the periphery of said circular air plate assembly comprise radially inwardly extending recesses from the peripheral margin thereof, such that the inner wall of the blast tube forms a portion of the margin of each said orifice.
 4. A gun type oil burner as defined in claim 1 wherein said circular air plate assembly is provided with adjustable orifice means in the central portion thereof, adapted to provide a limited flow of air to the central part of the blast tube about the fuel nozzle. 